import java.util.Scanner;

public class Round {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入圆的半径：");
        float R = scanner.nextFloat();
        double C = Math.PI*2*R;
        double S = Math.PI*R*R;
        System.out.println("圆的面积为：" + C);
        System.out.println("圆的周长为：" + S);
    }
}
